Automatic telephone system



May 21, 1929. J. 1. BELLAMY AUTOMATIC TELEPHQNE SYSTEM Original Filed Dec. 4, 1924 9 Sheets-Sheet Juhn LBflam HIT:

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' I AUTOMATIC TELEPHONE SYSTEM Original Filed DEC. 4, 1924 9 Sheets-Sheet 6 [nus cu" Juhu [Bellamy 9 Sheets-Sheet 7 Jul-m LBEZZam J. 1. BELLAMY AUTOMATIC TELEPHONE SYSTEM Original Filed Dec. 4, 1924 May 21, 1929.

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AUTOMATIC TELEPHONE SYSTEM Original Filed Dec. 4, 1924 9 Sheets$heet 9 John Lfigllamy Patented May 21, 1929.

UNITED stares earner or anae ia FICE.

JOHN I. BELLAMY, U1 BROOKFIELD, ILLINOIS, ASSIGNOR, BY MESNE ASSIGNMENTS,

TO AUTOMATIC ELECTRIC INC., OF CHICAGO, ILLINOIS, A CORPORATION OF DELA- WARE.

AUTOMIATIG TELEPHONE SYSTEMI Application filed December 1, 1924, Serial No. 753,796. Renewed July 27, 1928.

The present invention relates to automatic telephone systems in general, but is concerned more particularly with multi-oiiice automatic telephone systems of the type in which directors are used to register, translate, and retransmit the telephone numbers; and the main object is the production of a new and improved telephone system of the foregoing character in which an intermediate distributing frame is provided common to a plurality of directors. In this respect, this application may be considered an improvement on the co-pending application otliichardson et 211., Serial No. 694:,482, filed February 25, 192i, and on the co-pending application of Bellamy, Serial No. 746,730, filed October 30, 1924. a

As a matter of review, it may be pointed out that a director oi the type disclosedhcrein is employed in a multi-oiiice telephone system primarily to promote trunking eficiency by permitting calls to all offices in the same loiality to be handled over the same group oi: trunks regardless of the niunericaldesignations of the offices, and also in order to promote trunking eiiiciencyby permitting calls to distant oiiices to be setup step by step through many intervening tandem oiiiees as maybe encountered during the process of trunking the call to the desired oflice. Specifically, the function of a director of the type disclosed herein is to register the otiice.

digits of a number and to transmit in accordance therewith the proper code digits to trunk the call to the desired office in accordance with the trunking arrangement to effect the send ing out of the desired code digits ineach case. Such an arrangement proves to be entirely sa'tisii'actory'iirom the'standpoint of regular operation but,'in addition to its more or less excessive cost, it provesto be a severe handi- These two groups of terminals are capin cases where alterations are. made 1n. the trunklng arrangement and consequently in the routing of calls, as it-is Il0BS.-'

sary to change the jumpers on the intermediate distributing frame of each and every director. Accordingly, the common intermediate distributing frame has been developed, i. e., circuit arrangements have been made whereby one, intermediate distributing 'l'rame serves for a plurality of directors, thereby considerably lowering the cost of the installation and facilitating changing the codes on a large number of directors when.

changes inthe trunking layout are made necessary from time to time.

While the present caseresembles the two prior cases mentioned in the foregoing in that it shows .a director system in which a single distributing frame. serves a plurality of directors, entirely diiierent circuit arrangements are used for accomplishing this result, and new principles of operation are followed, as will be pointed out.

According to one feature oi. the invention, the impulse stop conductors are each maintained at a different electrical potential. Before the transmission of a digit begins, the wiper controlling such digit is connected up to oneterminalof the test relay, after having been previously set. upon one of the impulse stop conductors, and the other terminal. of the test relay is brought into engagement with the impulse stop conductors in order. The testrelay' is energized from ground before the transmission of the digit and the accompanying testing operation starts, and it energizes upoireach succeeding step as long as a potential diiierent fro-m the potential of the preselected stop'conductor is encountered, but fails to energize when the preselected stop conductor is reached, because the same potential is now connect-ed to both of its terminals. The failure ofthe test relay to respond results in the termination of the digit.

According to a desirable modification of the above arrangement, the test relay is replacedfiby apolarized test relay which is energized in onedirection when the testing operationstarts and energized in the op posite direction. to terminate the digit when the next stop conductor beyond thepre-selected one is reached.

Other objects and features have-to do mainly with the circuit detailsinvolved in carrying out the foregoing These latter ohject-s and feature further perusal of the description.

Referring now to the drawings comprising Figs. 1.-10, inclusive, Figs.. 15, inclusive,

show by means oftheusual circuit diagrams,-

a 'sufficient amount of equipment in a telephone system embodylng the prlnclples of the invention to enable the invention to be understood and its utility appreciated; Fig. 6

shows a desirable modification of the arrangement shown in Fig. 4 for securing a number i of different potentials; and Figs. 7-10, inclu- -of-Figs. 2-5, inclusive. 7 I

sive, show a modification of the embodiment The equipment shown inFig. 1 comprises the substatlon A, the indlvi'dual line switch LS- at the exchange, 'the trunk circuit TC inserted in the trunk leading from the bank to line switch LS to the selector S, and the director selector DSindividual to the trunk "circuit TC and the equipment shown in Figs.

2'5,inclusive, comprises oneof the directors access ble to the director selector DS, to-

' gether with the intermediate I distributing frame IDF, Fig. at, which is common ,to this controlling the automatic switches.

The line switchLS is mechanically of'the' "usual rotary type in, which the wipers have no normal" position'and are-moved in a forward direction only, being advanced upon the back stroke of the associated stepping magnet ratherthan upon the forward stroke. 7 The trunkcircuit TC is provided primarily to enable a director to be temporarily asi Imal conductor 4. thereby making the calling linebusy and closing a circuit through switohing relay 5 and stepping magnet- 7 in series. At armaturelQ, line. relay .6 connects test sociated with the-connection, and comprises the usual line, release, and switching relays.

:The selector S is anautomaitc switch of the usual vertical and rotary type having bank contacts arranged in horizontal rows or levels. V 1

The director selector DS is similar to the line switch LS, both as regards its operation and also from a mechanical'standpoint.

The sequence switch S, Fig. 2, is a simple step by step switch having wipers 108 and 110 which are advanced in a forward direction by steppingmagnet 105 and which are re- 'storedto normal position under the control of release magnet106 whose circuit passes 1 through off normal contacts 107 and .is therefore'opened when the wipers reach their normal position. This sequence switch distrib 'utestheincoming impulse conductor to the varlous operating magnets of the director,

as will hereinafter appear.

i The sequence switch Sis, from a mechani- "cal standpoint, similar to the line switchL i and the director selector DS, and its function is to bring about the transmission ofthe varione series of impulses in their proper order.

s will'appear fully-upon a ing of jumpers The oiiice register OR, Fig. at, is, mechan ically,-an automatic switch of a type similar to theselector S, "Fig. 1, and its function is to register the two. otlice digits in any called" 7 the desired oiiice.

The digit registers i-l--i ii---si,inclusive, are each similar, mecnanicalty, to the sequence switch S, and their function is to register the four subscriberdigits of any number.

The sending switch S Fig. 3, is similar, meclmnically,to the sequence switch S. and

itsfunction is to count off the impulses as they] arebcing trzmsmitteiand to connect the test relay-205 to the various impulse stop conductors 111 regular order.

' The intermediate distributing frame IDF.

is connected between the multipled bank contacts of the ofiice registers, such as the office register O'R, Fig. i, and the ten'impulse stop conductors Eel-), so that the ofiice codes may be readily changed and so that the changcodes of a plurality of'directors.

I In order to enable the invention to be understood best, theoperations accompanying the setting up of a connection from the'line of substationaAto acalled line will nowbe described. For this purpose agwin be assumed that the subscriber at substation A desires to makea call and accordingly removes his receiver; 1

When the receiver is removed at substation A, a circuit isclose'd' over line conductors 2 and3 for line relay 6 of the line switch LS. Line relay 6 thereupon energizes and at armature 11 places ground on private norwiperM tolt'he junction of, switching relay 5 and stepping'magnet 7.. In case the trunk onwhich wipers of the line switch are standare standing is busy, test wiper 14 is in en gagementwith a grounded testcontactand switching-relay .5, being shortcircuited, does not energize. 'Steppingmagnet 7 in this case energizes from the grounded testwiper l4,

and, being self-interruptin operates in a buzzer-like manner toadvance the wipers 13-15, inclusive, step idle trunkl.

When an idle trunk is reached,- which trunk, it will be assumed, is the one. com prising conductors l618, switching relay 5, being nolonger short circuited, energizes in series with steppingjmagnet Stepping point changes the Office by step in search of an Cir magnet 7 does not operate at this time on accountof the high resistance of switching relay 5. Upon energizing, switching relay opens the test circuit and prepares the holding circuit at armature 9; and at armatures 8 and 10 disconnects line conductors 2 and 3 from line relay 0 and the ground and extends them by way of wipers 13 and 15, conductors cuit for switching relay 5 of the line switch LS before the slow acting line relay 6 has had time to deenergize.

In the trunk circuit TC, as a further result of the energization of release relay 26, a circuit is closed at armature 31 for switching relay 37 and stepping magnet 68 ot the 'di.- rector selector DS in series, and test wiper ?5 is connected at armature 82 to the junctionof switching relay 37 and stepping magnet 68. Accordingly, the director selector DS operates in a manner similar to that just described in connection with the line switch LS to select an idle director. When an idle director is reached, switching relay 6? energizes; opens the test circuit and places ground upon test wiper at arn'iature 71, thereby grounding release trunk conductor '79 of the seized director; connects up the operating conductor at armature 72; and at armatures 69 and 70 connects the conductors leading to line relay all of the selector S through wipers 73 and 7 1 to a normally closed bridge in the director including conductors 77 and 78 and armaturcs 19 and 21 and thcirresting contacts in multiple. Accordingly, line relay 41 ot the selector S energizes and closes at armature 50 a circuit for release relay -12, which energizes also, preparing the selector tor operation in the usual manner.

In the seized director, release relay E201 energizes over release trunk conductor 79 responsive to the groimding oi? the said conductor 79 by thcrlirector selector DS, as above pointed out, removes ground from the restoring conductors 1141 and at armatures 216 and 218; and opens the normal restoring circuit of the sending switch 5 at armature 217.

The above operations, it will be remembered, have all taken place responsive to the removal of the receiver at substation A, and

the circuits are now in readiness for the first digit in the desired number to be dialled. Accordingly. the subscriber at substation A turns his calling device for the first digit and line relay 25 of the trunk circuit TC is de cnergized'a corresponding number of times in the usual manner. Upon eachdeenergization, line relay 25 transmits an impulse of current to the director over the following path from ground by way of the resting contact and armature 20 of line relay 25, armature 72 and its working contact, wiper 76, impulse conductor 80, and series relay 101, Fig. .2, to wiper 110 of the impulse distributing sequence switch S. Vl iper 1.10 is normally in engagement with conductor 121 which leads to the vertical magnet of the otfice register OR, Fig. 4. Accordingly, the vertical magnet of the office register OR is energized once for each impulse of current transmitted to the director over the operating conductor 8, and the wipers 301304:, are raised step by step and come'to restopposite-the the series of impulses, an impulse of cur rent is transmitted to magnet during the interval required for relay 102 to fall back t-ffliel its circuit is opened. Magnet 105 thereupon energizes and advances wipers 108 and 110 into engagement with the second set of bank contacts lVhen the calling subscriber dials the second digit, th resulting impulses are transniitted over the previously traced circuit as far as wiper 110 of the sequence switch S and are then transmitted over conductor 122' to the rotary magnet of the office register OR. That being the case, wipers 301--30 1, are rotated step by step and come to'rest in on gagement with the desired set of bank contacts, which contacts, it will be assumed, are the contacts 305308. Series relay 101 is again energized with the result that the wipers 108 and 110 of the sequence switch S are advanced another step'at the end of the rotary movement of the office register OR. l Viper 10S. upon coming into engagement with the third associated bank contact, initiates the sending operation, and the sender, Fi 3, starts to send out the first of the ofiice code digits, as will be subsequently explained.

Re ponsive to the tour remaining manipulations oi? the calling device at substation A, the digits regisers l)R1DRl, Fig. 5, are operated over conductors 15115+l, re spectively, the wipers oi" the sequence switch Slicing a dvanccd one step at the end of each series ot impulses in the hereinbefore described nianner. 1

Considering now the oitice register OR, it will be remembered that the wipers 301-304 are in engagement with the bank contacts ly, when series relay 101 deenergizes at the end 305308,respectively, and it may be pointed noted that the first contact 305 is connected witlithe third impulsegstop conductor 248 by means of umper 309 ;-'the second contact st'op'conductor 2&7 by means of the jmnper 310; the'third contact 307 isconnected with the :fifthimpulse stop conductor 245 by neans ot' the jumper 311; and the fourth will I be advanced "autom contact 308 is not: connected to any of the impulse stop-condactors but left open. Accordingly, as'will be described hereinafter. three code digits 3, 7, and 5 will transinitte'd', owingto the connections made by the uinpers 309, 310,:1nd EH1, respectiyely and nodigit will be transmitted when wiper 304 is'connected' up because contrctSOS left dead, and the-sequence switch S, Fig.2.

P i t ir-e fourthrode-digit position aswill hereinafterappear. I

Returninfg now to the wipers 108and'110 are advanced into engagement with the third set oi? bank contacts immediatelyfollowing the termination I v I 'cuit closing relay 206, thereby preventing the of'the rotary movement of the ofiice register OR; Fin. 1, wiper 108 connects the interru'pter109 tothe start-conductor 116, whereupon impulse relay 202,. Fig. 3, 'connnences to. energize and deenergize under the control of interrupter 109 in order to transmit the necessaryimpulses to QXLCHd the connection. .40

Upon the first energization of relay 202 following 'thec'onnectinn' up of the interrupter 1005 armature 220 closes a circuit through "the resting contact and armatru'e 228 for stepping magnet 207 of the sending switch S .;,Stepp1ng magnet 207 thereupon ener- Q'lZQSLZHld moves the associated pawl. into engageinent'with. the next notch in the wiperdriving'ratchet,wheel but docs not move the .wipers 208and 209. Upon the foliowin r deenergization of impulse relay 202 the circuit of stepping magnet 207 is opened ar; mature 220, whereupon stepping magnet 207 deenergizes and advances the wipers 20S and 209. into engagement with the firstset of bank contacts. 7 Wipers 208. and 200 both engage -grounded contacts and pickup wiper closes a circuit for pickmp relay 203. Upon energizing, pick-up relay 203 removes the sh untfrom around armature 219'at arn'iature 221 closes at armature 222 a circuit from the normally closed contacts controlled by arma-.

ture 226Qthrough armature 215 and itsworlo ging contact, and over conductor 114 for stepping magnet 111 of the sequenceswitch S, which thereupon V energlzespreparatory -to s connected with the seventh impulse point at which 7 advancing the wiper-e112 and 113 prepares I the relay considerably.slower than the avero relay to pull up. Accordingly, it remains inert 01 a slight interval ai'terits circuitis ciosed.

Returning now to wiper 209, this wiper, upon-being advanced into engagement with its first associated contact extcnds ground throu h contacts 210 andthe resting contact k; x v and armature 260 to one terminal of testrelay 205. "The other terminal of test'relay 205 is connected throughconductor117, stop co'nouctor control wiper 113 of the sequence 'tch Fflhe first code digit stop conductor 301 of the oil-ice registerOR, bank 005.. and jumper 309 of the intermedistributing frame IDF to fthethird y 205., Fig. 3,-is energized by theporth a battery included between con- 2&3 and ground, and at armature 231 opensa point in the circuit of stop relay20t justprior to the 'energi'zation oi the stop cirenergg ization ofstoprelay 20% at this time.

Uion jener 'izinq rela 206 tries to; close a moved from around armature2l9 and its rest- U ing contact of impulse relay 202 at armature 221 of pick-up relay 203. Accordingly, upon the next eneng'iaation of nnpulso relay 202 undcr the'control the interrupter109, the

outgoing controlcircuit is opened at arriia ture 219; and at armature 220 the circuit of relay 206 is opened and the circuit of step;

in magnet 207 oi? the sequence switch S is closed. Accordmgly.v the stifl'ly ad usted stop-circuitrclosing' relay 206 quickly falls. back, and stepping magnet 207. energizes preparatory to again advan'cingrthe wipers 208. and 200. At contacts 210 magnet 20? disconnects wiper 209, thcreby bringing about the deenergization oitest relay205; This is done onfea ch'step of the switch S in order that test relay 205 will be ina deenergized condition at, the beginning eachstesting operat on. This 1 sures the stopping the sending operation at the correct point as will hereinafter appear. 1' v When impulse relay 202 subsequently 'deenerg zes. t aga n closes the outgo ng control circuit at armatur'e219, and at armature 220 opens the circuit of: stepping magnet 207 and closes the circuit of relay 206, which does not, however, pull. up immediately for the reasons above given. Stepping magnet 207 now deenergizes and advances wipers 208 and 209 another step. Test wiper 200 now engages the lirst impulse stop conductor 241, and, since this is not the stop conductor to which the otherterlninals of test relay 205 is connected by means of jumper 309 on the intermediate distributing "r'ra-n'ic IDF, test rclay 205 energizes again and disconnects stop relay 204 at armature 231 just prior to the pulling up of relay 206.

In the same way, impulse relay 202 again energizes and again opens the outgoing control circuit at armature 219, and wipers 208 and 209 are again advanced in the above man,

ner when relay 202 subsequently denergizes. This time, test relay 205 energizes from the section of the battery included between conductors 242 and 243 and prevents the energization of stop relay 204.

Upon the next energization of impulse relay 202, the third interruption is produced in the outgoing control circuit at armature 219.

At armature 220 stepping magnet 20'? is energized and at contacts 210 disconnects wiper 209, bringing about the dcenergization of test relay 205. When relay 202 then falls back, the outgoing control circuit is closed at armature 219, and at armature 220 the circuit of magnet 207 opened and the circuit of relay 200 is closed. Upon deenergizing, magnet 20? advances wipers 208 and 209 another step i and wiper 209 comes into engagement with the bank contact in which the third impulse stop conductor 243 terminates. Accordingly, test relay 205 is connected to the same conductor at both terminals and does not energize. That being the case, when the stil'lly adjusted stop-circuit-closing relay 206 energlass, it closes at armature 232 a circuit through the resting contact and armature 231, normally closed contacts controlled by armature 227, and resistance 234 for stop relay 204. Stop relay 204 now energizes and closes a locking circuit for itself at armature 227 which includes the working contact and armature 228, at the sametime opening its initial circuit; disconnects stepping magnet 207 from the working contact of armature 220 at armature 228; places a shunt around armature 219 and its resting contact at armature so as to prevent further interruptions in the outgoing control circuit; shifts "the circuit of magnet 111 ot the sequence switch S at armature 220 from ground through the normally closed contacts controlled by arn'iature 226 to ground through the working contact and armature 226, armature 231 and its resting contact, and armature 232 and its working contact; and at armature 230 disconnects test relay 205 from test wiper 209 and connects it to ground, whereupon relay 205 again energizes and opens the circuit of stepping magnet 111 of the sequence switch S at armature 231. Magnet 111 now deenergizes and advances the wipers 112 and 113 one step lViper 113 shifts the associated. terminal of thetest relay 205 :lromt-he first code-digit stop conductor 141 to the second code-digit stop conductor 142. Test relay 205 remains-energized because the second code-digit stop conductor 142 is connected to battery by way of the scvcnth impulse stop conductor 247 through wiper 302 of the ethos register OR, bank contacts 306,and jumper 310 on the intermediate distributing frame IDF.

It will be understood that the above operations all occur in quick succession and are completed before impulse relay 202 energizes again to bring about the deenergization of relay 206, Relay 206 continues to energize and deenergize under the control of impulse relay 202 for the time being, but no further results accompany such action As a further result of the above energization of stop relay 204, it connects the ground-- ed pick-up wi per 208 at armature 229 through interrupter contacts 211 to stepping magnet 20?. Accordingly, stepping magnet 207 operates with a quick vibratory movement and the wipers 20S and 209 are quickly spun around to the position shown in the drawings. the movement being stopped owing to pick-up wiper 208 leaving the last grounded bank con tact and arriving upon the dead contact shown. Asa further result of pick-up wiper 208 passingott the last grounded contact, the circuit of pick-up relay 203 is opened. This relay does not fall back immediately, however, owing to the fact that it is slow acting.

In the selector S, Fig. 1, line relay 41 deenergizes responsive to each of the three interruptions produced in the outgoing control circuit of the director, as above described, and, upon each deenergization, closes at armature 50 a circuit for vertical magnet 66 through armature 52 and its working contact and series relay 48. By the operation of vertical magnet 66', the wipers 62, are raised step by step and come to rest opposite the third level of bank contacts. 4 Relay 43 is energized in series with vertical magnet 66, and, being slow acting, maintains its armature attracted throughout the vertical movement. At armature 53, relay 43 closes, in conjunction with. oil normal contacts 49 which close upon the first vertical step, a circuit through interrupter contacts 87 of rotary magnet 48 for stepping relay 44. Stepping relay 44 accordingly energizes andcloses a locking circuit for itself at armature 54, and at armature 55 prepares a circuit for rotary magnet 48.

At the end of the vertical movement, slow acting relay 43 deenergizes and closes the rotary magnet circuit at armature 53. R0-

tary magnet 48 now energizes and advances the wipers 6062 'intoengagement. with the first set, of bank contacts in the third level,

48 now deenergizes and closes its interrupter contacts 67 again. 1 v i The further. operation now. depends upon whether the trunk terminating the first set of bank contacts. is busy ,or idle. In case this trunk is idle, switching relay energizes, seizing thetrunk. Assuming on the other hand that the trunk is busy, switching relay 45, being short circuitedby the ground p0 tential encountered on .the busy test contact by test wiper 61, does not energize, and step: pingrelay 44 energizes from this same ground potential and again closes the rotary magnet circuit; at armature 55, whereupon rotary magnet 48 energizes again and advances the wipers 60-62 another step. 1

This alternate operation of steppingrelay 44 and rotary magnet 48 continues as described untilan idletrunk is reached, which .trunk, it will be assumed, is the one comprising conductors 6365. When rotary magnet 48 falls backlandvcloses its interrupter contacts 67 after having advanced the wipers into engagement with-this idle trunk, switching relay 45, belng' no longer short circulted, energizes from the grounded release trunk conductor 17 through off normal. contacts 49,

interrupter contacts 67, and. stepping relay 44. Stepping relay 44, however, does not energize at. this time onaccount of the high resistance of switching relay 45. Upon ener gizing, switching'relay 45 disconnects ground fromarmature 50 of line relay 41 at armature 58, thereby opening the circuitof release relay; 42 5 opens the test circuit and prepares the holding'circuit at armature57 ;jandiat arma-' tures 66. and Y59 disconnects the incoming line conductors from line relay 41 and extends them by way of-wipers 60 and62, the'bank contacts with which these wipers are mengagement, and conductors 63 and 65 to the line relay of the selector .to which the seized trunk extends; The line and release relays of this selector '(not shown) now energize and prepare the switch for operationin the usual manner. 1. I

In the director, pick-up. relay 203 falls back at the end of the interval for which it is adjusted; places another shunt across conductors 77 and. 7 8 at armature 221; opens a further point in the circuit of step ing magnetlll of the sequence switch S at armature 222; disconnects relay 206 at armature 224, whereupon relay 206 stops vibrating; and at armature 223 opens the locking circuit of the slow acting stop relay 204; Accordingly,

' after the interval forwhich it is adjusted,

1,71ae1a Y 1 Upondeenergizing, stop relay 204 I removes i at armature 225 the shunt around contacts 219 and 221; opens a further point in its own locking circuit and prepares its initial energizing circuit again at; armature 227 shifts the working contactiof armature 222 of relay 203 back to ground againatarmature 226; opens a point in the restoringcircuit of the switch'S. at armature 229; shifts the lefthand terminalof test relay 205 from ground back to wiper 209 throughcontacts 210 at armature 230, whereupon relay 205 deener gizes; and at armature 228 places stepping magnet 207 under the controlof armature 220 of impulse relay 202 again. ,Accordingly,

stepping magnet 207 startsto energize and deenergize again underthe control of lmpulse relay 202 and the second code digit is transmitted in the same way as the first, the difference beingthat the right handterminal of test relay 205' is now connected by'stop.

conductor control wiper 11 3 of the sequence switch S over the second code-digit stop conductor 142, wiper 302, hank contacts 306, and jumper 310 to the seventh impulse stop conductor 247 instead of over conductor 141'to the third impulse stop conductor 243,,as in' the previous case. Therefore, it willbe at once appreciated that, as the counting switch 7 S continues .to advance from contact to con tact, test relay 205 will continue to energize upon each stepiuntil wiper 209 arrives upon the bank contact in which the seventh impulse stop conductor247 terminates, and that when this contact is reached, test relay 205 fails to pull as was the case in the preceding example when the contactsassociated with the third impulse stop conductor 243 was reached. The failure of test relay 205 to pull. up at this time results in the energization of stop relay 204 with the hereinbefore described results. Accordingly, the second code digit 7 is terminated and the sequence switch S is advanced one step. 7 i I Responsiveto the transmission of the sec igiiaeis tact, the right hand tern'iinal of test relay 205 is connected through the third code-digit stop conductor 143, wiper 303, bank contact 307, and jumper 311 to the fifth impulse stop conductor 245. The transmission of the third code digits proceeds in the same manner as the transmission 01 either of the first two digits until wiper 209 oi? the sequence switch S arrives upon the bank contact in which the fifth impulse stop conductor 521- terminates, and, when this contact is reached, no circuit is closed for relay 205 because both terminals are connected to the same conductor, and stop relay a energizes with the hereinbetore described. results. This time, as before, when the left hand. terminal of relay 205 is connected to ground by armature 230, test relay 205 energizes again and opens the circuit of stepping magnet 111 01 the sequence switch S at armature 231. Accordingly, magnet 111 deenergizes and the wipers 112 and 113 are advanced another step. Stop conductor con trol wiper 113 connects the right hand terminal of test relay 205 through the fourth code digit stop conductor 14 1 and. wiper 304 of the oilice register OR to the dead contact 303. Accordingly,- test relay 205 now decnergizes and at armature 5231closes a point in the circuit of stepping magnet 111 of the sequence switch S. As far as the ultimate result is concerned, it is immaterial whether the stop circuit closing relay 200 has fallen backby this time or not, but, assuming that it has, stepping magnet 111 does not energizes at this time, but it energizes again as soon. as relay 206 pulls up again and completes the circuit at armature 232. When relay 2013 again deenergizes, magnet 111 deenergizes and advances the wipers 112 and 113 anotherstcp. Wiper 113 is now in engagement with the first subscriber-digit stop conductor 151 which extends to the wiper 4101 of the digit register DR1. Accordingly, test relay 205 now energizes again over conductor 151 and, opens a point in the circuit of stepping magnet 111 at armature 231 to prevent the further advance of the sequence switch S at this time. lit may be pointed out that a circuit will he closed for test relay 205 over conductor 151 and wiper 101 at this time, regardless of. the position of wiper 401. For example, it wiper 4:01 is still in its normal position due to the fact that the calling subscriber has not yet dialled the first subscriber digit, test relay Q05 energizes due to battery supplied through stop relay 204C and conductor 200. the resistance 234. being inserted in theloclring circuit of relay 201 to prevent relay 205 from being short drcuited at this time by the locking circuit of relay 2041. It will now be seen that stoprelay 201 will be held energized in series with test relay even after relay 203 deenergizes and opens the lockin circuit oi? stop relay 204. at arma ture 2-13, and that stop relay 20 1 will be mai ntained energized to prevent the starting of the transmission of the first subscriberdigit until after wiper e01 moves ofi its normal contact when the dialling of the first digit finally begins. In the same way, the trans mission of each of the other subscriber digits is delayed until after the dialling of such digits has begun, in case the digit is not completely dialled before the sequence switch S arrives in the corresponding position.

It, on the other hand, the first subscriber digit has been dialled, wiper 4:01 is standing on one of its other contacts and relay 205 is energized from one of the stop conductors 2 11 250. i

It will now be seen that the code digits 3, 7, and 5 have been transn'iitted and 'that'the fourth code digit position has been skipped by the sequence switch S because no jumper connected. to the fourth contact of the set in use on the intern'iediate distributing frame. It will, of course, be apparent that, in case the occasion arises, as many code digit positions as desired may be skipped. In Fact, all code dig s are automatically skipped in case all tour jumpers are omitted, the operation being similar to the operation occurring during the transmission ofthe digits, with the exception that stop relay 201 is energized right away to place a shunt around armature 219 and its resting contact at armature 225 and prevents any interruption in the outgoing control circuit.

Responsive to the transmission of the third. code 5, the selector switch seized in response to the transmisison oi? the secondcode digit 7, raises its wipers opposite the h'tth level of bank contacts and selects a trunk line leading to the desired oihce.

in the director, as soon as relays 203 and 20 1 have both fallen back, the transmission of the first subscriber digit begins. The transmission of this digit continues as long'as test relay205 continues to energize over wiper 4:01, but when wiper 200 of the sending switch S arrives upon the stop conductor on which wiper 101 is standing, relay 205 fails to pull and the digit is terminated. in the usual manner.

The sequence switch S, of course, advances another step and wiper 113 connects test relay 205 to the second. subscriber-digit stop conductor 152 and the second subscriber digit is accordingly transmitted in accordance with the setting of wiper 4.02 of the digit register Di t-2.

1n the same way, the sequence switch S is again advanced, and the third subscriber digit is controlled over stop conductor 153 and wiper 403 of the digit register DR-3. Similarly, the fourth subscriber digit is controlled over the fourth subscribendigit stop conductor 15 i and wiper 40 1 of the digit register DR1.

the sequence switch S again' advances upon the termination of the tourthsubscriber digit, and wiper113 passes from the bank contact associated with the fourth subscriberit disconnects conductors 16 and 18 at arma tures 33 andllf) and extends them to the CD1? responding conductors leading to the selector S, at the same time disconnecting the line conductors of the selector S from the control bridge of the director, leaving the established connect-ion under the direct control of the calling subscriber. Line relay 25 deenergizes upon being disconnected and at rmature 29 disconnects the combined switching and operating conductor from swi'ching lay 27 and connects it to groiuid. At armature 28, relay 25opens the circuit of release relay 26 which subsequently deenergizes; removes ground from release trunk conductor 17 at armature 30, leaving the connection held upby the ground supplied over release trunk conductor 64 of the trunk comprising conductors 6365; opens another point in the previouslyiclosed test circuit of the director selector DS at armature 32; and at armature 31 opens the circuit of switching relay 67 0f the director selector DS,whereupon relay 67 deenergizes and disconnects the associated wipers.

In the director, test relay 205 is short circuited upon the above mentioned closure of the locking circuit of switching relay 27 of the trunk circuit TC, and thereupon falls back, permitting-at armature 231 the circuit of stepping. magnet 111 of the sequence switch S to be closed at armature 232 of relay 206. This results in the wipers 112 andv 1.13 taking another step, whereupon wiper 113 picks up battery and test relay 205 energizes again,

preventing the sequenceswitch S from advancing further at this time. 7

When the wipers of the director selector D8 are disconnected by relay 57, as above pointed out, ground is removed from release trunk conductor 79, whereupon release relay 201 of the director deenergizes; disconnects conductor 114 from the sending circuit at armature 215'; 'closes' the normal restoring circuit of the sequence switch S at armature 216; closes the normal restoring circuit of the sending switch S at armature 217; and at armature 218 places ground on conductor 233 in order to release the sequence switch S, the ofiice register OR, and the subscriber- I digit registers DR-1-DR--4. i The release otthe sequence switch Sis brought about upon the energization of release magnet 106 through 011 normal contacts 107 and the circuit of release'magnet 106 isopenedat oft normal contacts 107 when the wipers 108 and 110 reach their normal. position. 'The release of the vother switches over conductor 233 occurs in the same manner. Itmaybe pointed out that the closure of the normal restoring circuit of the sending switch S? at armature 217 does not have any particular utility in this present case because the said sition but of utility in cases where the calling subscriber replaces his receiver while the sending switch. is in an oil normal position. Responsive to the closure of the normalyre storing circuit of the sequence switch S at an mature 216, stepping magnet 111 operates over conductor 115 and through wiper 112 and advances the wipers the remaining step to their normalposition because it interrupts its own circuit in this case.

. About the only other point that need be n'ientioued at this ti mein connection with the restoration of the director, is that pick-up relay 203 deenergizes probably at about the same time that the release relay of the trunk circuit TC falls back and that stop relay 204 deenergizes shortly thereafter. The director now in its normal condition and is ready to be used'in' handling another call.

Regarding the desired connection, may be pointed out that a thousands selector, :1 hundreds selector, and a connector in the called oiiice, have been operated responsive hen the called man answers the rlnging currentis disconnected andthe talking circuit is closed. The two subscribers nowconverse. p

When the receiveris replaced at the substation A upon the termination of the conversation, the ground'potential. is removed'in the usual manner, from release trunk conductor64 of the trunk comprising conductors 63-65, whereupon switching relay 45 of the selector S, switching relay 27 of the trunk circuit TC, andswitching relay 5 of the line switch LS deenergize. The deenergization of relays 5 and 27 restores conditions in the respective circuits tonormal. The deenergization of switching relay 45 01 the selector S results in the closure at armature 58 of a circuit through armatures 50 and .52 and 011' normal contacts 4? tor release magnet 46. Release magnet 46 energizes and restores the -wipers 60-62 to their normal position, wheresending switch S is already in it's normal po-' shows an alternative arrangement for supplying the necessary potentials to conductors 2 1L250, Fig. The potential supplied to conductor 250 is, before, the full battery potential, while the potentials supplied to conductors Q-flLQ-TS are derived potentials and dit er from each other by the amount 01 drop across the associated resistances. This arrangement is especially recommended for the use in situations where is impractical or undesirable to the exchange battery. The total resistance across the battery will, of course, depend upon the number of directors using the common intermediate distributing frame, and the larger the nun'iber, the lower the resistances must he made in order to avoid excessive itnbalaiicihg 'dueto the connection of the test relays, such as test relay 205, Fig. 3, across the impulse stop conductors during the testing operations of the various directors. I

ltel erring now particularly to Figs. 7-10, these drawings should be substituted for Figs. 25. They show a director similar to the one shown in Figs. 2-5, in that a common intermediate distributing trains is provided. The principal diitlerence lies in the testing arraiigement provided for terminating the digits. in this case,-a polarized relay is used which does not respond to current flow in one direction and accordingly, it fails to operate until a given conductor is reached and is passed by the test wiper of the sendingswitch, whereupon it operates due to the reversed current to close a circuit for the stop relay.

Assuming now that the director shown in Figs. 25 is disconnected from conductors 77-80; that the director shown in Figs. 7-10 is connected to these same conductors; and that the latter director is seized by the director selector DS, Fig. 1, by way of conductors 7780, release relay 502, Fig. 8, energizes over conductor 79; removes ground from the restoring contacts in the bank of the upper wiper of the sequence switch S at armatures 510 and 511; and at armature 512 opens up the release circuit of the register switches and oi: the sequence switch S, Fig. 7. The setting of the register switches of this director proceeds in the manner hereinbetore described, and the upper wiper or the sequence switch S connects the interrupter 581 to conductor 532 as soon as the otlice register OR, Fig. 9, is set.

It will be assumed that the oflice register OR is set upon the contact set shown in the drawings. It will be noted that the first con tact is cross-connected to the first impulse stop conductor 511; the second contact is cross connected to the sixth impulse stop conductor 5416.7 the third contact is cross connected to the tenth impulse stop conductor 550; and the fourth contact is cross connected to the skip conductor 560. It will now be explained how this cross connection effects the sending out of dead contact. gization of pick-up relay 503, it closes at the tapped battery.

the ofice code 1 60 and effects also theskipping of the fourth code digit position.

V1 hen the interrupter 531 is connected up to conductor 532, the stepping magnet of the sending switch S commences to energize and deenergizethrough the resting contact and armatrue 519 of stop relay 504:, and the wipers 506 and 507 are advanced step by step. Upon the firststcp of wipers 506 and 507, Wiper 506 comes into engagement with a grounded contact and closes the circuit 0t piclcup relay 503. Relay 508 now energizes and at arma- .e 516 connects the stop conductor distributing wiper of the sequence switch Fig. 7, at armature 516 to the polarized test relay 505 through armature 520 and its resting contact. This, however, cannot produce any result at this time, because wiper 507 is on a As a further result of the enerarmature 514 a circuit through armature 518 and its resting contact for the stepping magnje't of the sequence switch S, which thereupon energizes preparatory to advancing its wipers. Relay 503 also removes the shunt from around the sending contacts of the magnet of the sequence switch 8 at armature 513.

The circuits are now in condition for the outgoing control circuit over conductors 77 and 78 to be opened at the right hand contacts of the stepping magnet of the sending switch Accordingly, upon the next energization of the said stepping magnet, the outgoing control circuit is opened, and, upon the following deenergization, the outgoing control circuit is again closed and wiper-S 506 and 507 advance another step; At this time, wiper 507 engages its second contact which is connected with conductor 51-2, the remaining contacts in bank of wiper 507 being connected in order to conductors 543-551, inclusive. With wiper 507 standing on conductor 542, the polarized relay 505 is included in the following circuit: from ground by way of conductor 541, F 1, the associated jumper, first contact in the selected set in the banlr of the ofiice register OR, first wiper of the office register, first contact in the bank of the lower wiper of the sequence switch S the said lower wiper, the associated conductor, armature 516 and its working contact, armature 520 and its restingcontact, relay 505, wiper 507, and conductor 5&2 to the first section 01 The current flow through test relay 505, atthis time, is in the right direction to operate it. Consequently, relay 505 energizes and closes a. circuit for stop relay 1. Stop relay 504 now energizes and places a short across conductors 77 and 7 8 at armature 517, thereby terminating the first digit 1. At arinature 518, relay 50 1 opens the circuit of the stepping magnet of the sequence switch S? to permit this magnet to deenergize and advancethe associated wipers. At the working contact of armature 518: relay 504; closes a locking circuit for itself. At armature 520 relay 504 disconnects the lower wiper of the sequence switch S from testrelay 505 and connects it instead to the skip relay 501. This relay,however,ris marginally adjustedand does not energize at this time on account of the comparatively low tion, the automatic rotation ceases and the "circuit of pick-up relay 503 is opened. Pickuprelay 503 deenergizes after a short interval and places the usual shunt across the impulse circuit at arn'lature 513, and at armature 514 opensthe locking circuit of stop relay 504 with the result that relay 504 deenergizes shortlythereatter. v V

li hen relay 504: dsencrgizcs, the sending switchS is started in operation tor the transmission of thesecond code digit 6. The lower wiper of the sequence switch S is now standingon its second bank contact and is connected accordingly through the second wiper of the office register OR, and the jumper. as: sociated with the bank contact on which this wiper is standing, to the sixth impulse stop conductor Accordingly, when wiper 507 comes into engagement with the first live contact after the transmission of the firstimpulse inthe second codeldigit, a circuitis closed for test relay 505 through the section of the tapped battery included between conductors 542 and 5 16. does not close a circuit for stop relay 50 1- at this time, because its armature is attracted in the direction opposite to that in which it must be attracted in order to come into ongagement with the associated contact. The sa'mething is true upon each of the following steps of the sending switch until wiper 507 lands-on the bank contact in which conductor 5416 to inmates, at which time thereis.

no battery included in the circuit otrelay 505, andit obviously cannot energize in this case either. As soon, however, as wiper 507 lands on the bank contact in which conductor 547 terminates, which it does only after six interruptions in the outgoing control circuit have been produced, acircuit is closed through test relay 505 which includes the section of the tapped battery between the conductors 546 and 547. Accordingly, relay 505 energizes and terminates the second digit in the same manner as described in connection with the termination of the first digit.

From the foregoing, it may be seen that the third code digit to be transmitted the ductor 560, and the entire battery. energizing, relay 501 connects ground to the second, th1rd,.and fourth contacts in the bank 1,71as1e digit 0, and that in this case, the polarized 7 test relay 505 does not receive current in the proper. direction to close its contact until test wiper-507 of the sending switch 3 arrives upon the lastlive contact in its bank,

which is the one with which conductor551 is associated At this time, since the lower rive upon the fourth at of bank contacts.

The; lower wiper is now connected with the fourth wiper on the ofiice'register OR. Since all the code digits have been transmitted, it is now desired to cause the sequence switch 'S to skip the fourth digit position. Accordingly, the fourth contact in the set shownin the bank of the o'liice register OR is connected by means of a umper to the skip conductor 560. This conductor is maintained at a much higher potential than any of the other conductors, with the result that the marginal skip control relay 501, Fig. 8, en rgizes through the working contact and armature 520, working contact and armature 516, lower wiper and iourth contact of the sequence switch S fourth wiper or the office register OR, the contact upon which it is standing, the associated jumper, skip con Upon of the upper wiper of the sequence switch S with the result that this switch is automatically advanced from the fourthiposition to the fifth position. The advance of the wipers of the sequence switch S stops when tll-fiftl1 position is reached and relay 501 dcenergizes. V i

It is thought that with the foregoing description in mind, the operation of the director in transmitting the tour subscriber digits willbe readily understood. Briefly, it may be pointed out that the various contacts in the banks of the digit registers are connected in multiple with the corresponding contacts on the left hand'side of the intermediate distributing frame lDF, and that the normal contacts of the registers are all multipled together and connected to stop relay 501,'Fig. 8, so as to hold, this relay energized to prevent the starting of the transmission of a: given subscriber digit until the corresponding register moves off normal.

lVhen the wipers of the sequence switch S are advanced one step at the end of the trans mission of the fourth suscriber digit, the

ground through relay 501, Working contact and armature 520, and the working contact and armature 516 to conductor to operate switching relay 2? of the trunk circuit TC, with the result that the connection is switched through as hereinhefore described. The sequence switch S remains in this condition until release relay 502 deenergizes responsive to the removal of the ground potential from release trunk conductor 79, which occurs in the hereinbefore described manner. Responsive tothe deenergization of release re lay 502, all'the switches of the director are restored to normal position in the usual manner.

It may be pointed out now that, since the second, third, and fourth contacts in the bank of the upper wiper of the sequence switch S are grounded at armature 508 of relay 501 when the said relay 501 energizes, the sequencc switch S can he made to advance a'uton'iatically past any one of its code-digit positions, barring the first, by merelyconnecting the corresponding bank contacts to the skip conductor 560.

Another point not mentioned hereinbet'ore is that armature 515 of pick-up relay 503 is provided to maintain release relay 502 energized and to maintain the director guarded as long as the sending switch is in an oil normal position. This is done in lieu of pro viding a normal restoring circuit for the sender, and, in case a calling subscriber hangs up during the transmission of a digit, the director will be held engaged until such transmission is finishcd and until the sending switch restores to normal and pick-up relay 503 deenergizes.

lVhat is claimed is:

l. in atelephone "for extending connecti li es in one oi ice to called lines in other ofiices, directors in the first oflice for controlling said switches, a sender for each director having hank contacts, multiple connections between the bank contacts of all said senders, and means for controlling any sender over said multiple connections.

2. In a telephone system, automatic switches for extending connections from calling in one oiiice to called lines in another office, directors in the first otiice tor controlling said switches, an office register tor each director, sets of bank contacts for said registers multiplied together, a sender for each director, bank contacts for said senders multipled tog-ether, and a distriliuiting frame haw ing sets of contacts on one side thereof connected in multiple with the banks of said registers and having sets of contacts on the other side thereof connected in multiple with the banks of said senders.

3. In a telephone system, a call director in cluding a register and a sender, said register and sender each having a wiper and bank of contacts, multiple conductors extending between the bank contacts of said register and said sender, a test relay having two terminals connected, respectively, to the said Wipers, means for setting the wiper of said register upon a desired contact to predetermine a digit, means for operating said sender to transmit impulses andto advance its wiper as said impulses are being sent, and means controlled by said test relay responsive to the operation of said sender for terminating the transmission of impulses in accordance with thesetting of said register.

4:. In combination, a plurality of control conductors each maintained at an electrical potential different from any of the others, a est relay having two terminals, registering means for bringing one of said terminals in engagement with one of said conductors, and "counting means for bringing the other terminal of said test relay into engagement with said conductors successively.

5. In combination, a plurality of control conductors each maintained at an electrical potential different from any of the others, a polarized test relay having two terminals, re means for bringing any one of sa d terminals into engagement with one of said conductors, and counting means for bringing the other terminal of said test relay into engagement with said conductors successively.

, 6. In a call director, a sequence switch having a plurality of positions, a registering device toreach of said positions, means for positioning said registering devices on separate contacts, jumpers connected to certain of said contacts, meanstor transmitting a series of impulses in each position of said sequence switch which corresponds to a registering device positioned on "a contact to which a jumpor is connected, and means responsive to the omissionof the jumper from any one of said contacts for causing the said sequence switch to automatically skip the position which corresponds to the registering device positioned on such eontact. V

"I. In a director, a sending-c'oiitrol sequence switch having a control wiper and a restoring wiper, a bank of contacts for each Wiper, 'a relay and means forconnecting it to said control wiper, a source of current connected to one of the contacts in the bank of said control wiper for energizing said relay, and contacts on said relay for grounding certain contacts in the bank of said restoring wiper to automatically advance both wipers beyond a predetermined position.

8. In an automatic telephone system, directors for controlling the automatic switches, a sender in each director including a counting device, a distributing frame common to said directors. contacts in each counting device connected in multiple with terminals on one side of said frame, means in each counting 

